Notched can body



Nov. 18, 1969 H. D. BARTELS NOTCHED CAN BODY Filed May 25. 19s? 1 N VEN TOR HERBERT D. BARTELS I (Pmfl I AWQ/ Qjwh/W Afronmns United States Patent 3,478,921 NOTCHED CAN BODY Herbert D. Bartels, Palo Heights, lll., assignor t0 Continental Can Company, Inc., New York, N.Y., a corporation of New York Filed May 25, 1967, Ser. No. 642,670 Int. Cl. B65d 7/04, 7/36 U.S. Cl. 220-62 14 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a metal can body having a Welded side seam and wherein the ends of the can body are flanged preparatory to the double seaming of cans thereto. In the flanging of the can body the extreme ends thereof are circumferentially tensibly stressed and the can bodies are subject to cracking. The undue stressing of the extreme ends of the can body during fianging is prevented by a notching arrangement which relieves 'the circumferential tensile stresses.

This invention relates in general to new and useful improvements in can body construction and more particularly to a welded seam can body.

When a can body is flanged preparatory to the securement of ends thereto by a double seaming operation, the metal of the extreme ends of the can body is elongated approximately 8 percent. As a result, the can body ends are circumferentially tensibly stressed, to an extent which may cause cracking. When the can bodies have welded side seams, the tendency of the can bodies to crack is increased. This may be due to several reasons. First, in the area of the welded seam, the thickness of the metal is substantially double that of the remainder of the can body with the result that the resistance to elongation of the double thickness area is much greater and the elongation which would normally occur in the double thickness area must occur in the adjacent metal. Second, when the metal from which the can body is formed is a relatively hardened metal, the metal immediately adjacent the side seam becomes softened due to annealing thereof and is subject to greater elongation. Third, the metal immediately adjacent to the welded seam may be thinner than the remaining metal of the can body either due to the mechanical cleaning of the metal prior to welding or to the action of the welding rolls during the welding operation.

In accordance with this invention, it has been found that the circumferential tensile stresses whichare induced by fianging may be relieved by a notching system. It is, however, necessary that the notching system be of a nature wherein it in no way interferes with the formation of a proper double seam. Accordingly, the specific arrangement and position of the notching system is critical.

It has been found that a notching system having notches disposed immediately adjacent the welded side seam at the opposite sides thereof and wherein the notches are relatively shallow and preferably formed with a radius punch produces highly desirable results. It has also been found that other notching configurations, as well as score lines will satisfactorily function under certain conditions.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings:

In the drawings:

FIGURE 1 is a fragmentary perspective view of an "ice end portion of a flanged welded seam can body and shows a typical crack formed therein.

FIGURE 2 is a plan view on a reduced scale of a body blank formed in accordance with this invention.

FIGURE 3 is a perspective view of an unflanged can body formed in accordance with this invention.

FIGURE 4 is a fragmentary perspective view similar to FIGURE 1 and shows a flanged welded seam can body formed in accordance with this invention.

FIGURE 5 is an enlarged fragmentary plan view of a corner of a body blank and shows a preferred notching arrangement.

FIGURE 6 is a fragmentary plan view similar to FIG- URE 5 and shows a modified notching arrangement.

FIGURE 7 is a fragmentary plan view similar to FIG- URE 5 and shows a score line arrangement.

This invention particularly relates to can bodies having welded side seams wherein the can bodies are formed from body blanks of a thin metal as compared to conventional can body constructions. This thin metal is work hardened. In order to assure a uniform welding of the side sea-m thereof, it is preferred that the edges of the blank to be welded, be free of contamination. A practical method of accomplishing this is by way of a mechanical abrading operation wherein there is a slight thinning of the metal.

The body blank is formed into a cylindrical configuration in the customary manner, after which the side seam is welded. The heat generated in the metal along the side seam during the welding operation partially flows into the adjacent metal of the can body and is dissipated. However, the heating of the metal adjacent the side seam is sufficient to anneal the work hardened metal with the result that the metal of the can body circumferentially adjacent the welded side seam is softer than the remainder of the metal and is subject to greater tensile elongation. Furthermore, because of the thinning thereof, either due to the abrasive cleaning operation or because of the effect of the welding rollers thereon, the metal circumferentially adjacent the welded seam is further subject to greater elongation when tensibly stressed. In addition to this, inasmuch as the metal of the welded side seam is substantially twice as thick as that of the remainder of the can body, the metal of the welded side seam does not elongate proportionally and, therefore, the body material immediately adjacent the side seam is placed under severe stress to provide the normal increment of elongation plus the amount not contributed by the non-yielding side seam.

When the above described can body is flanged, at the extreme end thereof it is subjected to an elongation on the order of 8 percent. During fianging, the entire extreme end portion of the can body is circumferentially tensibly stressed. Additionally, the flanged portion of the can body has the internal surface thereof axially tensibly stressed and the external surface thereof axially compressibly stressed.

With reference to FIGURE 1, it will be seen that there is illustrated a welded seam can body which is generally referred to by the numeral 10. The can body 10 is provided at the illustrated end thereof with a flange 11 preparatory to the securement of an end thereto by means of a double seaming operation. The double thickness of the welded side seam 12 is clearly visible in FIGURE 1.

During the fianging of the end portion of the can body 10, for the aforementioned reasons and the stressing thereof in the general direction of the arrows shown in FIG- URE l, necking down or notching occurs adjacent the welded side seam 12 and the flanged can body 10 cracks as at 13. Inasmuch as the axial extent of the notch 13 is normally greater than that of the metal which is incorporated into a double seam, it will be readily apparent 3 that the can body is defective to the extent that it cannot be utilized.

At this time it is pointed out that the failure due to cracking illustrated in FIGURE 1 occurs only when the welded side seam 12 provides an effective bond entirely to the end of the can body. In the event there is improper welding at the extreme end of the side seam, there is a tendency for the imperfectly formed welded bond to separate and for the flanged end to tear circumferentially.

It has been determined that cracking of the can body due to the circumferential tensile stresses resulting from flanging may be eliminated by incorporating in the body blank a notching system, a preferred embodiment of the notching system being in the form of a shallow notch 14 disposed on each side of the welded body seam 12, each notch 14 opening out through the extreme end edge of the can body 10.

Referring now to FIGURE 2 in particular, it will be seen that there is illustrated a body blank from which the can body 10 is formed. The notching system is provided in the body blank 15 While it is still in a fiat state. Thereafter, the body blank 15 is shaped into cylindrical form with the side edges thereof overlapped and the welded side seam 12 is formed. The notches 14 are then disposed on opposite sides of the welded side seam 12, as is best shown in FIGURE 3.

The can body 10 of FIGURE 3 may have the extreme ends thereof flanged in any desired conventional manner. In view of the provision of the notches 14 closely adjacent to the side seam 12 and on opposite sides thereof, it will be seen that the portion of the can body 10 between the notches 14, which portion includes the welded side seam 12, is merely folded over during the flanging operation without any undue circumferential stressing thereof. While the remainder of the extreme edge of the can body 10 is stressed during the formation of the flange 11, there are no stress areas where undue stressing will occur and accordingly, the flanging will be without fear of cracking.

With reference to FIGURE 4, it is pointed out that there will be circumferential stressing of the can body 10 axially inwardly of the notches 14. However, the stressing of the metal of the can body axially inwardly of the notches 14 is not nearly as great as that which occurs along the extreme end portion of the can body, and the stresses set up in the metal are not suflicient to cause cracking.

At this time, it is pointed out that the shape, depth and position of the notches 14 are critical. In the first place, the depth of the notches 14 must be held to a minimum in order to provide for the proper forming of the required double seam during the securcment of a can end to the can body 10. Next, the notches 14 must have a shape which will eliminate the formation of stress points generally along the periphery of the notches. Further, the notches 14 must be sufiiciently close to the welded seam 12 to perform their stress relieving function.

Referring now to FIGURE 5, it will be seen that there is illustrated enlarged details of one corner of the body blank 15. Normally, the body blank will have the opposite surfaces thereof covered with a coating 16. That surface of the body blank 15 which becomes the internal surface of the can body 10 will be coated with a suitable protective coating whereas the exterior surface will be coated with a decorative coating. In order to provide good electrical contact both between the overlapped edge portions of the body blank and between the edge portions and welding electrodes, the side edges of the body blank are cleaned as at 17. The width of the cleansed area 17 will at least be equal to the amount of overlap of the side edges during the formation of the welded side seam 12 and normally will be slightly greater to assure effective cleaning operation. Although the cleaning of the side edge portions 17 may be effected in various manners, it has been found that the most effective manner is by an abrading operation which also results in a minor thinning and weakening of the metal of the body blank 15.

It is preferred that the notch 14- be spaced outwardly of the area of the edge portions 17 when there is a thinning of the body blank during the cleaning operation. In accordance with this invention, the notch 14 is spaced from the extreme side edge of the body blank 15 a distance X. On a beverage can having a diameter of 2 inches, this should not exceed 0.250 inch. On the other hand, the minimum dimension of X should not fall below 0.040 inch.

It is preferred that the notching 14 be accomplished by means of a circular punch 18 having a radius with a dimension Y. It has been found that the most effective range of the dimension Y is from inch to inch. The die 18 is offset relative to the end edge of the body blank 15 so as to provide for a notch depth of a dimension Z. The notched depth preferably should be in the range of 0.010 inch to 0.030 inch.

Numerous notches have been formed in an effort to obtain a notch configuration which will accomplish the necessary stress relieving function and at the same time assure the formation of a proper double seam. When the side edges of the body blank 15 are cleansed by an abrading action, it has been found that a notch formed with a punch having a radius dimension Y of H inch, a spacing X from the side edge of the body blank on the order of 0.080 inch and a depth Z of 0.020 inch to 0.025 inch has provided the best results. The average depth of such a notch is approximately 0.022 inch.

Although from a tooling standpoint a notch formed with a circular punch is preferable, it is to be understood that the configuration of the notch 14 is not so limited. For example, in FIGURE 6 the body blank 15 is illustrated as being provided with a notch 20. The notch 20 has that ortion thereof adjacent the side edge of the body blank of a small diameter radius as at 21. The boundary of the notch 20 then slopes generally upwardly as at 22 away from the small radius portion 21. The sloping portion 22 is preferably arcuate but may be of a straight line configuration. Furthermore, if desired, the sloping portion 22 may have a relatively small radius curvature at the end thereof remote from the small radius portion 21 so that the notch 20 is generally U- shaped.

Referring now to FIGURE 7 in particular, it will be seen that the stress relieving means need not necessarily be in the form of a notch. For example, a score line 23 having the same configuration as the boundary of an acceptable notch may be provided. When the end edge of the resultant can body is tensibly stressed during the fianging operation, any cracking which would normally occur, will occur along the score line 23 and at a maximum would result in the complete breaking out of a chip24 defined by the score line 23.

At this time it is pointed out that although the problem of cracking during flanging is pronounced in a can body having a welded side seam, the problem is not restricted to can bodies with welded side seams, nor is the solution set forth above so restricted. It will be apparent from the foregoing that where the side seam of a can body is of a double thickness and the bond between the two thicknesses of metal is a secure one, the problem of flange cracking will exist. Although the problem is not as pronounced as it is in conjunction with Welded side seam can bodies, in can bodies having soldered side seams of the lap or hook and lap type are also subject to cracking problems during flanging. The above discussed notching of the extreme end edges of the body blank will solve the cracking problem in 'can'bodies having these types of seams, for example.

Although only several preferred embodiments of the invention have been specifically illustrated and described herein, it is to be understood that the configuration and dimensions of the notching system may be varied without departing from the scope and spirit of the invention, as defined by the following claims.

Iclaim:

1. An outwardly flanged bonded side seam metal can body, said can body having notch means formed in at least one of the flanges thereof on opposite sides of said bonded seam for preventing the cracking of said can body due to circumferential elongation during the formation of said flanges, and a portion of said side seam being circumferentially intermediate said notch means.

2. The can body of claim 1 wherein the metal of said can body along said bonded seam has a greater resistance to circumferential elongation than the remainder of said can body whereby the metal of said can body at the ends thereof is subject to undue stress during the formation of said one flange.

3. The can body of claim 2 wherein the bonded side seam is a welded seam and the metal of said can body circumferentially adjacent said seam is softer than the remainder of said can body and subject to undue circumferential elongation.

4. The can body of claim 2 wherein the bonded side seam is a welded seam and the metal of said can body circumferentially adjacent said seam is thinner than the remainder of said can body and subject to undue circumferential elongation.

5. The can body of claim 1 wherein each of said notch means is in the form of a shallow notch.

6. The can body of claim 1 wherein that portion of said notch means adjacent said bonded seam is arcuate to minimize the existence of a stress point.

7. The can body of claim 1 wherein each of said notch means is formed to a depth ranging from 0.010 inch to 0.030 inch.

8. The can body of claim 1 wherein each of said notch means is formed to a depth ranging from 0.010 inch to to 0.030 inch.

9. The can body of claim 1 wherein said bonded seam is a lapped seam and said can body has free lap edges, and each of said notch means is formed to a depth ranging from 0.010 inch to 0.030 inch and is circumferentially disposed from a corresponding free edge a distance ranging from .040 inch to 0.250 inch.

10. The can body of claim 9 wherein said notch has a constant radius ranging from inch to 7 inch.

11. The can body of claim 10 wherein the optimum dimensions of said notch are on the order of a depth of 0.022 inch, a spacing of 0.080 inch and a radius of 7 inch.

12. The can body of claim 1 wherein each of said notch means is in the form of a score in said flange with the opposite ends of said score opening through the ends of said can body.

13. A blank for a bonded side seam can body, said blank being flat and of single ply and being flat, of a single ply and having two side edges and two end edges, and a notch formed in at least one end edge adjacent each side edge for facilitating elongation of said blank along said at least one end edge.

14. The can body of claim 13 wherein said notch is shallow.

References Cited UNITED STATES PATENTS 2,711,147 6/1955 Johnson 113120 1,643,252 9/ 1927 McCrery 220- 2,120,038 6/1938 ONeil 22075 3,179,284 4/1965 Valyi 220-75 HENRY S. JAUDON, Primary Examiner US. Cl. X.R. 22075 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 478,921 Dated November l8 1969 Inventor(s) HERBERT D. BARTELS It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

C01. 5, claim 8, before the period insert with constant radius ranging from 3/32 inch to 9/32 inch SIGNED mu SEALED JUN9 .1970

6%) Afloat:

mach" mam E. summm, JR. Attesting Offiwr Oomissioner of Patents 

